The proposed studies will continue investigations on the mechanism of biosynthesis and processing of the oligosaccharide chain of N-glycosidically linked glycoproteins. Efforts will be directed to providing answers to three questions. First, what is the site of transfer of the oligosaccharide chain from the lipid carrier to protein? Second, what are the detailed steps in the processing reactions that release glucose from the glucose-containing oligosaccharide chain? Third, what is the subcellular site and mechanism of addition of the "capping" sugars to the already completed core oligosaccharide chain attached to the protein?